Constructing homes, offices, boats and other structures has an ancient heritage. Despite all of the centuries of development, however, there can be difficulties and problems.
Construction is usually very labor intensive. Even a modest size structure usually requires the efforts of numerous individuals. This can be very costly. Simultaneously using the time of numerous individuals in an efficient manner can also be challenging.
The results of the construction effort can also be inconsistent. The appearance and quality of one structure can vary from another built from the same design. This can be caused by differences in the skills, efforts, supervision and techniques employed by those that work on the structures.
Construction may also result in wasted material. For example, when wood is used, standard, off-the-shelf lengths must often be cut to meet design requirements, resulting in waste. Construction using manual labor can also be very time-consuming, requiring months and, in some instances, years to complete. Construction can also be hazardous. Many construction workers are killed or seriously injured at construction sites, including about 500,000 in the United States alone.
Robotic systems have been used for Contour Crafting construction techniques, e.g., those in which curable cementitious fluids are applied in contours for a building layout/structure.
One robotic approach has used a gantry structure. Because of cost, speed of motion, ease of transport and erection at site, safety and energy conservation it is important for the gantry to be as light as possible. Design of light weight large gantries has been seen as a challenge for applications that require accuracy. Moreover, large size results in flexing of structural members the increase in stiffness of which usually results in added weight, given a material (aluminum, steel, composites, etc.) for the members. Also, material delivery to the nozzle of such gantry systems, which move in a large volume in the 3D space, have proven to be difficult to implement. Furthermore, delivery of the material to the nozzle given the localized motions of the nozzle (rotation and deflections) can also present significant challenges.
What is needed, therefore, are robotic systems that are lightweight while at the same time offering pronounced rigidity or stiffness for implementation in Contour Crafting construction and material delivery techniques.